Lumber-drying kiln



Aug. 26, 1930.

LUMBER DRYING Filed July 3, 1929 r Ari-L M. L. MUELLER KILN 4 Sheets-Sheet 1 INVENTOR. Moritz I. Mueller,

MW u! ATTORNEYS Aug. 26, 1930. M. MUELLER LUMBER DRYING KILN Filed July 3. 1929 4 Sheets-Sheet 2 INVENTOR.

Mon'iz I. Muellef,

BY I

A TTORNEY5 Aug. 26, 1930. M, L, MUELLER 1,773,744

LUMBER DRYING KILN Filed July 3, 1929 4 Sheets-Sheet 5 K IN VEN TOR.

Mani: .Z. Mueller,

A TTORNEY Patented Aug. 26 1 930 wAsHINGrojN, nssienon'ro GENERALIDRY KiLTN moiurz IL. (MUELLER; or SEATTLE,

coMrANn-oi rommnn,

unseen; A 'oonronarron ,Applic'ation filed mm 'ilhis; invention "relatesflto lumber drying.

kilns of the character of that shown in my Joe-pending application, Serial Number 346,667,, filed March 12th,1929, and it has for its-obj ectto provide-a kiln presenting marked teatnreslof advantage'and improvementiover the devices of the prior art, as-avill be more particularly pointediout in the detailed d9? scription which follows;

In the accompanying drawings: V

Fig. 1 is a View partly in plan and partly horizontal section of a kiln constructed in accordance With the invention,

V Fig. :2 is a vertical sectional view there through,-

Fig. 3

View,

Fig. 4 is is a transverse vertical sectional a fragmentary longitudinal and sectionaliview upon an enlarged scale,

; parts emitted,

Fig. 5 is alview partly inhorizontal sec tion'an'd partly in plan of a modified form of g 4 Fig. 6 is a longitudinal sectional View of the kiln illustrated in Fig. 5,1vith certain of the F g. Tis a fragmentary longitudinal sec- "tlOllEtlVlEW through apart :of the kiln, upon enlarged scalegand Y of the mod-ified form of kiln. i

In the form of the invention illustrated n Figs. its 4, each kiln chamber-comprises the side 73115 5, which rest upon the" concrete foundation '6, and an arched .roo-f 7,Wh1ch is termed upon the arc of acircle. Theair cu lating means'consis'ts ofa battery of fans.

8 that are mounted upon a line shaft'9, the latter being suspended by hangers 10 from the central portion-of the dome-like roof. Thecppcsitesides ot the interior ofthero'of are divided into'separate chambers 11 and lg hy alongitudinally extending zig-zag pan' tition 13. This partitioncomprises' the longitudinallyeiitending runs 14' and the trans verse runs 15 and 16, andit is in these lat- '-ter runs that the fans 8 are disposed; The

,tansmay have "their blades setto discharge I re in opposition-t0 each other; That is,'th'e fans '8 8 in Fig. 1, may discharge toward each other when the line shaft is rotated in one F-ig. 8:is a transverse vertical sectional'view 1929; {Serial No. 375,800.

"directionanddischarge awayifrom each other when the line shaft is rotated in the other direction, Thus; it will be clear that the H vchamber 11' may be either the dischargeor the s "intake chziniherfor the fans, according to direction of rotation, and that the same -is true with resipectto the chamber 12.;H0W- even; the fansrmay all discharge in thesame direction, if desired. y 7 Batteries-of steamipipes or like air heating means are disposed, aswindicated at 16,1 and it Will be understood that any other suitable air. conditioning,elements, commonly enil ployed inglumher drying kilns nay be disposedin the path of themovingairh v 2 By referring toFig, 1,'it will be seen that the dispositioning got the v"longitudina1 runs 14:, oi the partition, createsa series'of bays A,

along :theleng-th of-the line shaft, and immediately below the ceiling or roof. A separate fresh lair-intake pipe 18 is disposed in the 1100f above each of thesebays, said pipes be- ;mitted :to the bays upon either sideof the :tans. Thevents @provided by these freshair pipes permit fresh air to enter each fan in equal -volume,' or permits stale air to escape in-equ'al quantity uniformly throughout the lumber spaced longitudinallyalong the kiln. "These vents also-fact as inspection and hand Jholes afo-rthe bearings of the fan on the-line length Olfafill81=;-'kll!l. Thi s-wassures even humidity-lreduction with respect to every load'ot shaft, so that these hearings may he kept I properly tightened and lubricated,- and may be frequently inspected without the necessity 20f the operator entering the interior of the kiln. "In"someftypes' of-kilns; heretofore proposed, the'intake ,ofifresh' ,air to :the fresh'air duets hasheen tronika point adjacentthe end at the k iln ,fand througlrfresh-air conduits" disposedin a sort of basement beneath the kiln. Not only are such basements expensive to construct, but it 1s extremely dlflicult to secure an even flow of air throughout the length; of the kiln where the air has to be taken in from an end of the duct, because the drag or friction on the air, slows its flow to such an extent that those portsremote from the entrance end of the duct do not receive the same free supply of air as those ports adj acent the entrance endof the duct. The most desirable' achievement in dry kiln construction is to secure such a combination and correlation of the parts as willinsur'e absolute umformity of drying conditlons throughout the length and he ght and width ofthe; kilns. If'uniformity of drying conditions is not attained, then degrading of the lumber results, because if any one portion of common operating members toninsure that each closure will be opened to'the same degree, I am able to secure absolute uniformity of air flow throughout the entire lengthof the kiln, and l do this in conjunctionwith aircirculating apparatus dis osed immediately below a roof of stream ineconstruc r tion, which aids in maintaining a steady and even flowof air laterally of the kiln, past the heating unit 16, and transversely throughthe piles of lumber 25, that are piled in spaced courses upon-trucks 26, mounted to travel on trackrails 27. line shaft by any suitable driving means, such as the motor 28, and drive chain connections 29.

To close the space above the piles of lumber'against cross flow of air, which might interfere with the forced circulation through the piles of lumber, I dispose panels longit'udinally of the kiln and at such angles that they coact with the chambers 11 and 12, in I forming large throats at the entrances to the spaces 31 and32 between the sides of the piles of the lumbera'nd the kiln walls.

The; device of the present application is like that of my copending application,above referred to, in that the forcing of hot air downwardly into the chamber'32' (see Fig. 3) causes a'lateral diffusion of the air into the lumber, due to the opposing forces setup by the downwardly moving body of air encountering the air which tends to start to rise again after it has lost the downward momentum imparted to itfby the fans. sofa very large volume of air is greatly facili- The moving tated bv the constructiondescribed, because of the stream line effect of the roof and the Rotation is imparted to the versa. prevent air, which leaks past the door and character, it is essential that the air passages be free and unobstructed. By attaining this object in the construction of the kiln, I am able to use these very simple and cheap fans to move large Volumes of air over the. surfaces to be dried, in a'short time.

A-further advantage of the arrangement described, is that the locating of the radiation in the roof and adjacent the fans, aids in increasing the air flow by creating a suction or rising tendency of the air toward the intake sides of the fans. Another difiiculty experienced in lumber drying kilns is obv'iated by a feature of the present construction in that the panels 30 are terminated shortof the end wall of the kiln, as indicated at 33 (see Fig.2).

By virtue'of this construction, any air leakage about the doors 34, through which the trucks are introduced into the kilns, is neutralized. It has been the experience that air leakage about the doors atv the ends of the kilns has interfered with the maintenance of uniform drying conditions with respect to those loads of lumber adjacent said doors. By disposing the air circulating means overhead and by providing the special entrances 33'to the air circulating means at a point between the doors and the end truck loads of lumbers, air leakage about the doors is neutralized and its deleterious effects prevented. That is to say, the fans are rotating in one direction, air leakage around one door is drawn directly into the circulatory system instead of having to pass through a load of lumber onits way ts the circulatory system, while a blast of hot air is discharged downwardly over the other door, and vice The construction described acts to around the door from passing through the ends of the loads of lumber which adjoin the door, in its travel to a suction chamber, which is normallylocated farther away from the door than the entrances 33. Since automatically operated dampers'of' various kinds are in common use in conjunction with'the operation of lumber drying kilns, it will be readily understood that the automatic operationof the dampers constituted by the caps 19, of the fresh air pipes, is within the purview of my invention.

The form of the invention illustrated in Figs. 5, 6,7,- and 8, is very similar to that llEU Ill)

mes-air,

trom the form illustrated in F 's; 1 to in r that the undcritace of the re i of the kiln, is on thearc'of a parabola, instead ofbeingupon thearc of a circle, and that the 'ings 10 of the line shaft of the fan are supported upon the transversely ext-ending concrete beams 4:1,.hy which the s de walls Steam pipes, orcther suitable heating means are disposed, as indicated at 43. A cut-off ban plate 41 1 Mini.

carries (a canvas battle tip 4T5 at'its lower edge, which rests upon the upper surfaces of the plles of lumber, and prevents the cross passage ofth'e air currents. The formation at the roofupon the arc eta parabola results in discharging the aircurrents against the side walls oithe kiln insuch manner that the side walls themselves constitute battles which impartv such a lateral kick back to the air currents as to direct'thein obliquely against the exposed edges'ot the boards that arepiled in spaced courses upon the lumber trucks, these boards, in turn, deflecting these obliquely discharged air currents laterally through thee-upper 'courses of the piles of lumber, while such air as cannot'findits I way through thesecourses'iast enou tinues down the side walls meeting the previously disch ly rising currents of air, is id sed laterally through the loivercourses of the piles of lumber, so that all portions oi' the load re ceive an'ample volume of heated air. The bay A formed between the transversely exe tending runs of thepart-ition have their bot tc-ms closed,,(see Fig. 8) by sheets 46. c A sheets, as well as the transit panels-3G, are removableto give. access'to the tan chambers. In both forms of the invention, the con tinued movement of warm air currents over the undersideof the ceiling, prevents. the condensate and resulting drip, so common in those types of kilns, in which the air circulatmeansisdisposed at thebottom 01 the kiln; disposingthe line shaft in the top of the kiln; the permanent ali nent of the same is secured, i p 7 Another advantage of disposing the circulating means overhead is that-'- the fans,

r ing upwardof the lziln and i their bearings and the associated air ducts are in a position where water, acids, sawdust,

chips oribroken stock cannot come contact with themg V In the employmentof kilnshaving the air ducts at the bottom o't thekilns, itgis com mon practice for the workmen to lwalk along 7 root whichcannet sag longitudinally or settle con locally, as'i's the case with fiatground foundations.

The pea-anion ofroof herein shows and" described possesses great strength and is very economical-to construct, while, atthe same time, having-the inherent advantage so commonly employed. l/Vhile it is possible to provide rounded corners with a flat roof; construction, to reduce eddy currents, the archediroof gives this effect at least expense, and with'increa-sed strength: By locating the tens with theirbearing stands on concrete beams, supported by Walls which" a'ctias trusses in transmitting the load to the ground, the alignment otthefan drive. shaft is. rendered much morepermanent than Where the tan system is located in a basement, and comprises bearings supported directly on "the ground and, therefore, subjectto local settlement. i

Further, whenthe fans arelocate d in a basement, it is impossible to inspect, repair or lubricate the same while the kiln is running, because or" the location of piles of lumber over the bearings, and; because of the heat of the kiln and the congested'relation with moving parts. By locating the fan equipmentabove the lumber, and under the ceiling and provid ing means for access tothe bearings oi the fan from the exterior of the kiln, a workman may see, orr'each the bearings without entering the kiln, and this is an important advan= Dropping of water, or condensate, sawdust,

pitch; broken pieces of lumber and the like whatever changes tairlycome within either the spiritior'the terms of the appended claims.

claim is: v I

1.. A kiln ofthe character described, having an arched roof, a partition disposed beneath said arched roof and dividing the space there beneath into two chambers, a plurality of'air circulating elements disposed in said partition, a plurality oi air intakes disposed iongit'udinallyalong the top of the kiln, and

means for operating all of said'intakes uniformlyto the same degreeand in unison. 2;"A kiln of the character described, hav

, ing anarchedroofla partition disposed beneath saidarched root and dividingthe space thereb n1eath into two chambers, a plurality .115 Having described my invention, what I of air circulating elements disposed'insaid artition, a plurality of air intakes disposed ongitudinally along the top of the kiln, means for operating all of, said intakes uniformly to the same degree and in unison, there being one of said air intakes for each air circulating means. 7

3. A kiln of thecharacter described, having an arched roof, a partition beneath said roof dividing the space therebeneath into two chambers, a plurality of circulating fans in said partition, a plurality of air intakes disposed longitudinally along said roof, a common operating member for each alternate, air intake, and another common operating member for the intermediate air intakes. i

4. A kiln of thecharacter described, havingxan arched roof, a partition beneath said roof, dividing the space'therebeneath :into two chambers, a plurality of circulating fans in said partition, a plurality of air intakes disposed longitudinally along said roof, a common operating member for each alternate air intake, and another common operating member for the intermediate air intakes, there being one of said air intakes for each of saidfans.

5. A structure of the character described, comprising an arched roof, the underface of which presents a curvature on the arc of a arabola, transversely of the kiln,'air circu ating means disposed beneath said roof and arranged to set up an air circulation lateral lyacross the kiln, a longitudinally extending partition in which the air circulating means is disposed, which divides the kiln longitudinally into two chambers, and a pluralty of fresh air intakes disposed longitudinally along the top of the kiln, each alternate air intake being common to one of said chambers,

and the intermediate air intakes-being common to the other of said chambers.

6. A structure of the character described, comprising an arched roof, the underface of which presents a curvature on the arc of a parabola, transversely of the kiln, air circulating means disposed beneath said roof and arranged to setup an air circulation laterally across the kiln, a longitudinally extending partition in which the air circulating means is disposed, which divides the kiln longitudinally into two chambers, a plurality of fresh air intakes disposed longitudinally along the top of the kiln, each alternate air intake being common to one of said chambers, and the in termediate air intakes being common to the other of said chambers, and a common operating means for all of the air intakes of one group, and a second common operating means forall of the air intakes of the othergroup.

7. A structure of the character described, comprising an arched roof, the underface of which presentsa curvature on the arc of a parabola, transversely of the kiln, air circulating means disposed beneath said roof and arranged to set up an air circulation laterally across the kiln, a longitudinally extending partition in which the air circulating means is disposed, which divides the kiln longitudinally into two-chambers, a plurality of fresh air intakes disposed longitudinally along the top of the kiln, each alternate air intake being common to one of said chambers, and intermediate air intakes being common to the other of said chambers, hinged covers for all of said air intakes, upstanding crank arms carried by said hinged covers, a common operating member engaging all of the crank arms of one of the groups of the air intake covers, and a common operating rod engaging all of the crank arms of the other group of air intake covers. 7

8. The combination with a kiln, of an air circulating means disposed between the roof of the kiln, and the lumber therein, and arranged to discharge air transversely of the kiln, there being an air passage between that portion of the lumber space of the kiln adj acent the entrance doors thereof, and the air circulating means to permit the direct drawing into the air circulation of the kiln of such air as may leak past said doors.

9. The combination with a kiln, of a longitudinally disposed series of fans beneath the roof of the kiln, and doors for said kiln, and a partition separating said fans from the lumber receiving space of the kiln, which partition terminates short of the end walls of the kiln to permit the direct entryinto the circulatory system or" the kiln of such air as may leak past said end doors of the kiln.

10. T he combination with a kiln having an arched roof, of a partition dividing the space within said group longitudinally into two compartments, a plurality of fans in said partition for setting up acirculation of air transversely of the kiln, an element extending longitudinally of the kiln which prevents transverse flow of the air across the tops of the piles of lumber in the kiln, and end doors for said'kiln, said members terminating short of the end walls of the kiln to leave passages through which air which leaks past the end 'walls of the kiln may find its way directly to the circulatory system of the kiln without passing through the ends of the piles of lumber.

11. A kiln of the character described, having an arched roof, a partition beneath said roofdividing the space therebeneath into two ohambershaving a series of oppositely facing bays, a plurality of circulating fans in said partition discharging into said bays, and

"an individual air intake for each of said bays.

12; A kiln of the character described, having an arched roof, a partition beneath said roof dividing the space therebeneath into two chambers having a series of oppositely facing bays, a plurality of circulating fans in said partition, discharging into said bays, and an individual air intake for each of said bays and means for operating the air intakes.

13. A kiln of the character described, having a'roof adapted to direct air circulation within the kiln, a partition disposed beneath said roof and dividing-the space therebeneath into two chambers, a plurality of air circulating elements disposed into said partition, 7 a plurality of airintakes disposed longitudi- 19 nallyalong the top of the kiln, andmeans for operating all of said'intakes uniformly to the same degree and in unison. p

14. A kiln of the character described, having a roof adapted to direct air circulation within the kiln, a partitionbeneath sai d roof dividing the space therebeneath into two chan1bers, a plurality of circulating fans in said partition, a plurality of air intakes dis- 7 posed longitudinally along said roof, a com 20 mon operatingniember foreach alternate air intake, and another common operating member for the intermediateair intakes.

In testimony whereof I affix my signature.

MORITZ: L. MUELLER. 

